// 题3
function Test3() {
    var friendName = "World";
    (function () {
        if (typeof friendName === "undefined") {
            var friendName = "Jack";
            console.log("Goodbye " + friendName);
        } else {
            console.log("Hello " + friendName);
        }
    })();
}
  Test3();
  // 结果：
  //
/**
 * 解析：变量提升
 *
 */